In conventional wireless cellular telephone networks, macro base stations provide wireless cellular coverage for mobile units. A macro base station comprises multiple transceiver units, outputs relatively high power (i.e. 10 watts or more) to its antenna(s) and is communicatively coupled to a telephone network via a backhaul connection. Because macro base stations output high power, they can provide large areas of coverage.
The capacity of a macro base station can be expanded to a limited degree by the addition of transceivers and antennas to the macro base station. Additional macro base stations can also be added to the network. However, these measures have limitations due to interference among macro base stations caused by their large coverage areas and high output power. In addition, signal attenuation caused by building structures (i.e. indoor penetration loss) can result in communication difficulties for mobile units when located indoors.
Wireless broadcast networks communicate information, such as radio, television, multimedia services and datacasting, to mobile receivers via wireless radio transmission. For example, a mobile telephone may be equipped for both two-way voice communications and for receiving broadcast transmissions. Alternatively, a dedicated receiver, such as a satellite radio receiver, may be used to receive broadcast transmissions. Examples of wireless broadcast networks include mobile digital broadcast television (also called DTV and Mobile TV) and satellite radio. Mobile digital broadcast television standards include Digital Video Broadcasting-Handheld (DVB-H) and Digital Multimedia Broadcasting (DMB). Satellite radio typically operates according to proprietary standards of the operators (e.g., SIRIUS Satellite Radio, Inc. and XM Satellite Radio, Inc.). A wireless broadcast system, such as for mobile digital broadcast television, may employ an antenna located on a transmission tower or building that outputs high power, similarly to a cellular telephone macro base station. Satellite radio operators may employ terrestrial repeaters located on buildings to improve reception in metropolitan areas.
The cell radius for such broadcast systems is relatively large (e.g., 15 km to 30 km) when receivers are located outdoors. However, as with cellular telephone networks, these broadcast systems can experience difficulties due to indoor penetration loss. For example, if a receiver is located indoors, an additional indoor penetration loss of 8 dB to 30 dB is common. This reduces the cell size significantly and often causes sufficient loss in signal strength to prevent proper signal reception.